Housings for electronic devices

ABSTRACT

Methods and apparatus for applying internal features or complex mechanical structures to a surface of a metal part are disclosed. According to one aspect of the present invention, a method for creating an assembly that includes a substrate and a molded piece involves obtaining the substrate, and forming at least one binding feature on a surface of the substrate. The method also includes molding on a surface of the binding feature and the surface of the substrate. Molding on the surface of the binding feature and the surface of the substrate mechanically binds the molded piece to the substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation patent application of U.S. patentapplication Ser. No. 15/178,499, filed Jun. 9, 2016 and titled “Housingsfor Electronic Devices,” which is a continuation patent application ofU.S. patent application Ser. No. 13/488,309, filed Jun. 4, 2012 andtitled, “Methods and Systems for Forming a Dual Layer Housing,” now U.S.Pat. No. 9,387,612, which is a divisional patent application of U.S.patent application Ser. No. 11/964,652, filed Dec. 26, 2007 and titled“Methods and Systems for Forming a Dual Layer Housing,” now U.S. Pat.No. 8,192,815, which is a nonprovisional patent application of andclaims the benefit of U.S. Provisional Patent Application No.60/949,780, filed Jul. 13, 2007 and titled “Dual Layer Housing,” thedisclosures of which are hereby incorporated herein by reference intheir entireties.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to forming features on metal parts and,more particularly, to applying internal features of complex mechanicalstructures to the surface of a metal part.

Description of the Related Art

The manufacture of devices that include metal parts often includes theformation of features, e.g., complex mechanical structures, on surfacesof the metal parts. In order to ensure the structural integrity of suchfeatures, the features are often affixed to the surfaces of the metalparts using an adhesive material. By way of example, an internal featurehas been obtained and glued in an appropriate location on a surface of ametal parts or housings.

Alternatively, internal features have been welded to the surface ofmetal parts or housings. Utilizing a welding process to attach internalfeatures to metal parts is limiting in terms of the number and thecomplexity of the internal features that is possible using a weldingtechnique. Furthermore, the cosmetic quality of a metal part may bedegraded as a result of a welding process. For instance, the heatassociated with a welding process may alter the shape and/or the colorof a metal part.

Internal features may also be formed using an injection molding process.When a manufacturing process includes an injection molding process, athrough-hole may be formed in a metal part or housing, and a plastic ora resin may be injected through the through-hole. The plastic or resinmay form a feature on one side of the metal part, e.g., a metal sheet,while additional plastic or resin may form an undercut on the other sideof the metal sheet. The undercut, in cooperation with the plastic orresin that hardens in the through-hole, may effectively serve to anchoror otherwise hold the feature in place. Often, the side of a metal sheeton which an undercut is located may be arranged to be exposed. That is,the side of a metal sheet on which an undercut is located may be anexternal surface of an apparatus or device. As such, the presence of anundercut on the side of the metal sheet may be aestheticallyundesirable, e.g., when the metal sheet is arranged to serve a cosmeticpurpose.

Therefore, what is needed are a method and an apparatus for efficientlyforming features on a metal part or sheet. That is, what is desired is asystem which allows features to be formed on one side of a metal part orsheet substantially without affecting the appearance of the oppositeside of the metal part or sheet.

SUMMARY OF THE INVENTION

The present invention pertains to molding a material onto a substratethat has binding features. The present invention may be implemented innumerous ways, including, but not limited to, as a method, system,device, or apparatus. Example embodiments of the present invention arediscussed below.

According to one aspect of the present invention, a method for creatingan assembly that includes a substrate and a molded piece involvesobtaining the substrate, and forming at least one binding feature on asurface of the substrate. The method also includes molding on a surfaceof the binding feature and the surface of the substrate. Molding on thesurface of the binding feature and the surface of the substratemechanically binds the molded piece to the substrate.

According to another aspect of the present invention, a method forcreating a substrate with a binding feature includes obtaining thesubstrate and creating at least one opening in the substrate. Anextrudable material, e.g., a ultra violet (UV) cured glue, is backfilled into the opening, and the extrudable material is extruded throughthe opening. Extruding the extrudable material causes the bindingfeature to be formed as a protrusion.

In accordance with still another aspect of the present invention, anelectronic device includes an electronic component that is substantiallyhoused within a housing. The housing includes a metal part and a moldedpiece. The metal part includes a first surface and a binding featurewhich has a binding surface. The molded piece is molded onto the firstsurface and the binding surface. The molded piece may include amechanical feature.

Other aspects and advantages of the invention will become apparent fromthe following detailed description taken in conjunction with theaccompanying drawings which illustrate, by way of example, theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be readily understood by the following detaileddescription in conjunction with the accompanying drawings, in which:

FIG. 1A is a cross-sectional side-view diagrammatic representation of anassembly that includes a metal part with squared, protruding bindingfeatures and a moldable piece molded thereon in accordance with anembodiment of the present invention.

FIG. 1B is a cross-sectional side-view diagrammatic representation of anassembly that includes a metal part with squared, undercut bindingfeatures and a moldable piece molded thereon in accordance with anembodiment of the present invention.

FIG. 2A is a cross-sectional side-view diagrammatic representation of anassembly that includes a metal part with angled, protruding bindingfeatures and a moldable piece molded thereon in accordance with anembodiment of the present invention.

FIG. 2B is a cross-sectional side-view diagrammatic representation of anassembly that includes a metal part with angled, undercut bindingfeatures and a moldable piece molded thereon in accordance with anembodiment of the present invention.

FIG. 3A is a cross-sectional side-view diagrammatic representation of anassembly that includes a metal part with rounded, protruding bindingfeatures and a moldable piece molded thereon in accordance with anembodiment of the present invention.

FIG. 3B is a cross-sectional side-view diagrammatic representation of anassembly that includes a metal part with rounded, undercut bindingfeatures and a moldable piece molded thereon in accordance with anembodiment of the present invention.

FIG. 4 is a process flow diagram which illustrates a method of formingan overall assembly that includes a metal part with a moldable piecemolded thereon in accordance with an embodiment of the presentinvention.

FIG. 5A is a process flow diagram which illustrates a method of formingprotrusions on a metal part by overlaying a porous mesh on a surface ofthe metal part in accordance with an embodiment of the presentinvention.

FIG. 5B is a process flow diagram which illustrates a method of formingprotrusions on a metal part by attaching flanges to a surface of themetal part in accordance with an embodiment of the present invention.

FIG. 5C is a process flow diagram which illustrates a method of formingprotrusions on a metal part by substantially stacking flange componentson a surface of the metal part in accordance with an embodiment of thepresent invention.

FIG. 5D is a process flow diagram which illustrates a method of formingprotrusions on a metal part by back filling micro perforations definedwithin the metal part in accordance with an embodiment of the presentinvention.

FIG. 5E is a process flow diagram which illustrates a method of formingprotrusions on a metal part by sputtering matter onto a surface of themetal part in accordance with an embodiment of the present invention.

FIG. 6A is a block diagram representation of a protrusion formed bystacking flange components on a substrate in accordance with anembodiment of the present invention.

FIG. 6B is a block diagram representation of micro protrusions formedusing micro perforations defined within a substrate in accordance withan embodiment of the present invention.

FIG. 7A is a process flow diagram which illustrates a first method offorming undercuts on a metal part that includes masking the metal partin accordance with an embodiment of the present invention.

FIG. 7B is a process flow diagram which illustrates a second method offorming undercuts on a metal part that includes masking the metal partin accordance with an embodiment of the present invention.

FIG. 7C is a process flow diagram which illustrates a method of creatingan undercut on a metal part that includes using computer numericalcontrol (CNC) equipment in accordance with an embodiment of the presentinvention.

FIG. 7D is a process flow diagram which illustrates a method of creatingan undercut on a metal part that includes using at least one laser inaccordance with an embodiment of the present invention.

FIG. 7E is a process flow diagram which illustrates a method of creatingan undercut on a metal part that includes using at least one hot probein accordance with an embodiment of the present invention.

FIG. 8 is a cross-sectional side view block diagram representation of anapparatus used to mold a piece onto a metal part in accordance with anembodiment of the present invention.

FIG. 9A is a cross-sectional side view block diagram representation ofan apparatus used to mold a piece onto a metal part that includesundercuts in accordance with an embodiment of the present invention.

FIG. 9B is a cross-sectional side view block diagram representation of ametal part, e.g., metal part 904 of FIG. 9A, interfaced with a moldcavity onto which a moldable material has been provided in accordancewith an embodiment of the present invention.

FIG. 9C is a cross-sectional side view block diagram representation of ametal part, e.g., metal part 904 of FIG. 9A, onto which a molded parthas been substantially attached in accordance with an embodiment of thepresent invention.

FIG. 10 is a cross-sectional side view diagrammatic representation of ametal part into which tapered perforations have been provided inaccordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Example embodiments of the present invention are discussed below withreference to the various figures. However, those skilled in the art willreadily appreciate that the detailed description given herein withrespect to these figures is for explanatory purposes, as the inventionextends beyond these embodiments.

The invention relates to methods and systems for applying internalfeatures or complex mechanical structures to a surface of a metal part,housing, or sheet. The metal part, housing, or sheet may serve astructural and/or a cosmetic purpose. That is, a metal element on whicha feature or mechanical structure may be formed may have a purelystructural purpose, a purely aesthetic purpose, or both a structuralpurpose and an aesthetic purpose. For ease of discussion, a metalelement will generally be described as a metal part, although it shouldbe appreciated that a metal element may be substantially any suitablemetal component associated with a device or an apparatus, such as ahousing, a sheet, or an insert.

The application of an internal feature to the surface of a metal partmay include forming a moldable component, e.g., a moldable componentwith highly complex mechanical features. Complex mechanical features mayinclude, but are not limited to including, structural members, frames,screw bosses, bridges, snaps, flexures, flanges, shelves, tapers,cavities, and/or pockets. A moldable component may be adhered orotherwise physically coupled to a metal part, e.g., a cosmetic metalpart such as a polished metal housing, using any suitable process. Byway of example, a moldable component may be adhered to a metal partusing an insert molding process that effectively molds the componentonto the metal part. An insert molding process may be an injectionmolding technique that injects molten material, such as plastic orresin, into a mold and allowing the molten material to contact andadhere to a metal part, i.e., a metal part located in the mold, as themolten material cools. The moldable material is arranged to adhere tothe metal part, and may be molded to include relatively complexmechanical structures.

In one embodiment, a metal part may be a portion or a component of ahousing of an electronic device. A metal part that is a portion of ahousing of an electronic device may be a bezel section, a front section,and/or a back section of the housing. The metal part may be fabricatedfrom a wide variety of metals, including, but not limited to including,alloys, stainless steel, and aluminum. Further, the metal part may becosmetically enhanced via polishing and/or other surface improvementtechniques. By way of example, a metal part may be polished stainlesssteel.

The ability to efficiently adhere relatively complex mechanical featuresto a metal part allows the integrity of a device which includes themechanical features and the metal part to be enhanced. For instance,when mechanical feature is effectively molded with a metal part, thebond between the mechanical feature and the metal part is relativelystrong. Relatively complex mechanical features that are effectivelymolded with a metal part may be utilized in a variety of differentdevices including, but not limited to including, portable and highlycompact electronic devices with limited dimensions and space. In oneembodiment, a device may be a laptop computer, a tablet computer, amedia player, a cellular phone, a personal digital assistant (PDA),substantially any handheld electronic device, a computer mouse, akeyboard, a remote control, substantially any computer accessory, and/orsubstantially any computer peripheral.

Creating binding features on a surface of a metal part effectivelypromotes the adherence or the binding of a moldable plastic material,e.g., a moldable plastic material that may be formed to include acomplex mechanical feature, to the metal part. For instance, bindingfeatures that are protrusions which extend from the surface of the metalpart may allow the moldable plastic material to adhere to theprotrusions and, hence, essentially have an increased binding area thatallows the moldable plastic material to bind to the metal part. Theadditional binding or contact area between the metal part and themoldable plastic material provides a stronger bond between the metalpart and the moldable plastic material. Alternatively, binding featuresmay be undercuts or voids which effectively extend below a surface of ametal part. Such undercuts or voids also provide additional surface areato which moldable plastic may bind and, thus, adhere to the metal part.

In general, binding features, or features that enable a molded piece tomechanically interlock with a metal part, may take substantially anysuitable form. With reference to FIGS. 1A-3B, examples of bindingfeatures that are used to form assemblies which include a metal part anda moldable plastic feature will be described in accordance with anembodiment of the present invention. Referring initially to FIG. 1A, anassembly, e.g., a molded metal part, that includes a metal part withsquared, protruding binding features and a moldable piece molded thereonwill be described in accordance with an embodiment of the presentinvention. An assembly 100 includes a metal part 104 on whichsubstantially squared protrusions 112 are formed. Protrusions 112 may beintegrally formed on metal part 104. Alternatively, protrusions 112 maybe attached to metal part 104. Examples of processes that are suitablefor forming protrusions 112 on metal part 104 will be described belowwith reference to FIGS. 5A-E.

Protrusions 112 generally extend past a moldable surface 114, i.e., asurface of metal part 104 onto which a molded piece 108 is to be bound.Molded piece 108 is bound to surface 114 and to protrusions 112 or, morespecifically, to the surfaces of protrusions 112. In other words, moldedpiece 108 effectively molds around protrusions 112 and, hence, adheresto the surfaces of protrusions 112. Molded piece 108 may, in oneembodiment, be arranged to include complex mechanical features (notshown).

As will be understood by those skilled in the art, extending the heightof protrusions 112 relative to a z-direction 118 increases the surfacearea of protrusions 112. As such, increasing the height of protrusions112 includes the overall surface area that may be used by molded piece108 to adhere to metal part 104. Therefore, the adhesion of molded piece108 to metal part 104 is improved as the height the surface area of abinding surface is increased.

In lieu of forming squared protrusions 112 on metal part 104, squaredvoids or undercuts may instead be formed on a metal part. FIG. 1B is across-sectional side-view diagrammatic representation of an assemblythat includes a metal part with squared, undercut binding features and amoldable piece molded thereon in accordance with an embodiment of thepresent invention. An assembly 100′ includes a metal part 104′ on whichsubstantially squared undercuts 116 are formed. The formation ofundercuts will be discussed below with respect to FIGS. 7A-E.

Undercuts 116 extend below a moldable surface 114′ of metal part 104′. Amolded piece 108′, which may include mechanical features (not shown), isbound to surface 114 and to the surfaces of undercuts 116. In general,increasing the depth of undercuts 116 with respect to a z-direction 118′increases the surface area associated with undercuts 116 and, hence, theoverall surface area of metal part 104 to which molded piece 108 mayadhere.

The shape and size of binding features may be arranged to increase thesurface area of a binding surface and, hence the strength of a bondbetween a metal part and a moldable piece. In general, the greater thesurface area of a protrusion or an undercut, the larger the bindingarea. In one embodiment, a protrusion may include a top flange portionthat effectively forms an undercut, and provides a surface onto which amoldable piece may effectively grab. FIG. 2A is a cross-sectionalside-view diagrammatic representation of an assembly that includes ametal part which supports a protrusion with a top flange and a moldablepiece molded thereon in accordance with an embodiment of the presentinvention. An assembly 200 includes a metal part 204 on whichprotrusions 212 with a top flange portions 220 are formed. Top flangeportions 220 include undercut surfaces 222 which enable a molded piece208 to effectively grab thereon when molded piece 208 molds aroundprotrusions 212. Extending the height of protrusions 212 relative to az-direction 218 increases the surface area of protrusions 212. Further,extending the width of undercut surfaces 222 relative to an x-direction226 also increases the surface area of protrusions 212 and, hence, theoverall binding surface to which molded piece 208 may be bound.

Angled, undercut binding features that provide a surface onto which amolded piece may be bound may be provided on a metal part. FIG. 2B is across-sectional side-view diagrammatic representation of an assemblythat includes a metal part with angled, undercut binding features and amoldable piece molded thereon in accordance with an embodiment of thepresent invention. An assembly 200′ includes a metal part 204′ on whichundercuts 216 with angled bottom portions 224 are formed. Portions 224include surfaces 230 which enable a molded piece 208 to effectively grabthereon when molded piece 208′ is molded in undercuts 216.

Protrusions and undercuts may take on a variety of different shapes thatprovide an increased binding surface area. In one embodiment,protrusions and undercuts may take an approximately mushroom shape,e.g., a rounded shape. FIG. 3A is a cross-sectional side-viewdiagrammatic representation of an assembly that includes a metal partwith rounded, protruding binding features and a moldable piece moldedthereon in accordance with an embodiment of the present invention. Anassembly 300 includes a metal part 304 on which substantially mushroomshaped, rounded protrusions 320 are formed. When a molded piece 308 isbound to metal piece 304, molded piece 308 is bound to the surfaces ofprotrusions 320. That is, molded piece 308 effectively molds aroundprotrusions 320 and, therefore, adheres to the surfaces of protrusions320.

FIG. 3B is a cross-sectional side-view diagrammatic representation of anassembly that includes a metal part with rounded, undercut bindingfeatures and a moldable piece molded thereon in accordance with anembodiment of the present invention. An assembly 300′ includes a metalpart 304′ on which substantially mushroom shaped, rounded undercuts 324are formed. When a molded piece 308′ is bound to metal piece 304′,portions of molded piece 308′ fill undercuts 324, thereby binding moldedpiece 308′ to the surfaces of undercuts 324.

FIG. 4 is a process flow diagram which illustrates a method of formingan overall assembly that is suitable for use in an electronic device andincludes a metal part with a moldable piece molded thereon in accordancewith an embodiment of the present invention. A process 401 of forming anoverall assembly that includes a metal part and a molded piece, e.g., amolded plastic part, adhered thereto begins at step 405 in whichparameters for a molding process are selected. Selecting parameters fora molding process may include, but are not limited to including,selecting injection mold parameters, selecting parameters associatedwith the plastic used in the molding process, and selecting metalparameters associated with the molding process. In addition, moldconfiguration parameters, properties of the plastic, and properties ofthe metal part may also be selected.

After parameters for a molding process are selected, a metal part with asurface to be molded is provided in step 409. As previously mentioned,the metal part may be a component of a device. By way of example, themetal part may be a component of a housing associated with an electronicdevice, or may be an insert that is intended to be incorporated into theelectronic device. The surface to be molded is typically the surface ofthe metal part onto which a molded piece is to be adhered or otherwisebound. If the metal part is a cosmetic, external part of an electronicdevice, the surface to be molded is generally a surface of the metalpart that is arranged to be substantially internal to the electronicdevice.

The surface to be molded may include attachment or binding features whenobtained in step 409. However, if the surface does to be molded does notinclude attachment or binding features, the attachment or bindingfeatures may be applied to the surface to be molded in an optional step413. Various methods of applying attachment or binding features to thesurface of a metal part will be described below with respect to FIGS.5A-E and FIGS. 7A-E.

The metal part is situated, as for example placed or secured,substantially within a mold cavity of a molding device in step 417. Forexample, the metal part may be positioned within the mold cavity whenthe molding device is opened. The metal part is located at a desiredposition relative to the mold cavity and, thus, relative to the internalmoldable part that will be applied thereon. Positioning the metal partappropriately within the mold cavity may be accomplished with a robotarm associated with a robotic system. Situating the metal partsubstantially within the mold cavity may also include preparing the moldcavity and the metal part, adjusting the temperature associated with themolding device, and/or closing the molding device.

Once the metal part is situated in the mold cavity, injection moldmaterial is injected in step 421 into the mold cavity. The injectionmold material is generally arranged to flow into the mold cavity, tocome into at least partial contact with the metal part, to harden withinthe mold cavity, and to adhere or otherwise attach to the metal partsituated in the mold cavity. In one embodiment, a substantially moltenplastic or a resin is injected into the mold cavity. The injection moldmaterial may generally mold around attachment or binding features on thesurface of the metal part. The mold cavity may be configured to define aplurality of relatively complex mechanical features. As such, theinjection mold material may effectively be molded such that therelatively complex mechanical features are defined.

The injection mold material is allowed to cool, cure, harden, orotherwise set. The shape of the cured or hardened injection moldmaterial may include relatively complex mechanical features, e.g., ifthe mold cavity is configured to define relatively complex mechanicalfeatures. From step 421, process flow proceeds to step 425, the metalpart, with a feature formed from the injection mold material adheredthereon, is removed from the mold cavity. That is, the molded metal partwhich includes a metal member and a molded member is removed from themold cavity. By way of example, once the injection mold material curesor hardens in contact with the metal part, the molding device may beopened, and the molded metal part may be substantially ejected from themolding device.

After the molded metal part is removed from the mold cavity, postprocessing steps may be performed on the molded metal part in step 429.Such finishing steps may include, but are not limited to including,machining, threading, forging, polishing, and/or applying a coatinglayer. It should be appreciated that the finishing steps may beperformed either on the metal member of the molded metal part, themolded member of the molded metal part, or on the overall molded metalpart. Once post processing or finishing steps are performed on themolded metal part, the molded metal part is assembled into an electronicdevice in step 433, and the process of forming an overall assembly thatincludes a metal part and a molded piece which is suitable for use in anelectronic device is completed. In one embodiment, the molded metal partis a housing that is arranged to substantially encase electricalcomponents of an electronic device.

Attachment or binding features formed on the surface of a metal part mayinclude protrusions and undercuts. With reference to FIGS. 5A-E, methodsassociated with forming protrusions on the surface of a metal part tofacilitate the attachment of a moldable part thereon will be described,while with reference to FIGS. 7A-E, methods associated with formingundercuts on the surface of a metal part to facilitate the attachment ofa moldable part thereon will be described in accordance with anembodiment of the present invention.

FIG. 5A is a process flow diagram which illustrates a method ofeffectively forming protrusions on a metal part by overlaying a porousmesh on a surface of the metal part in accordance with an embodiment ofthe present invention. A process 501 of effectively forming protrusionsbegins at step 505 in which a substrate with a mold surface, i.e., asurface onto which a molded piece is to be bound, is obtained. In oneembodiment, the substrate is a metal part and the mold surface is thesurface of the metal part onto which a moldable piece is subsequently tobe adhered. Once the substrate is obtained, locations on the substrateonto which a mesh is to be applied are determined in step 509. A mesh,which may be a metal mesh, generally includes openings that provide anattachment surface which may be molded over by a molding material. Thatis, a moldable material is molded around the porosity of the mesh. Theuse of the mesh provides additional surfaces to which the moldablematerial may be bound. In one embodiment, the mesh may be substantiallyapplied over a majority of the surface of at discrete points about thesurface. It should be appreciated, however, that the mesh may instead beapplied at relatively few discrete points about the surface.

After locations for the mesh are determined, the mesh is positioned atsuch locations in step 513. Positioning the mesh at appropriatelocations may include cutting the mesh and overlaying the mesh on thesubstrate at the appropriate locations. The mesh effectively formsprotrusions to which a moldable material such as plastic or resin maysubsequently bind. The process of effectively forming protrusions byoverlaying a porous mesh is completed upon positioning the mesh.

FIG. 5B is a process flow diagram which illustrates a method of formingprotrusions on a metal part by attaching flanges to a surface of themetal part in accordance with an embodiment of the present invention.Flanges, as will be appreciated by those skilled in the art, may have avariety of different shapes and sizes. By way of example, flanges may be“T” shaped, mushroom shaped, or rectangularly shaped. A process 521 offorming protrusions on a substrate, e.g., a metal part, using flangesbegins at step 525 in which a substrate is obtained. Once the substrateis obtained, flanges of a suitable shape are obtained in step 529. Thesize and the shape of the flanges may vary, and the flanges maygenerally be formed from a wide variety of different materials. Flangesmay be preformed, e.g., flanges may have a predefined shape, or flangesmay be arranged to be substantially created through a soldering process.After the flanges are obtained, the flanges are attached to thesubstrate in step 533. In general, the methods used to attach a flangeto a substrate may include, but is not limited to including, applying anadhesive to the flange and mating the flange with the substrate, andsoldering the flange to the substrate. The process of formingprotrusions using flanges is completed once the flanges are attached toa substrate.

Flanges which are used to form protrusions on a metal part may becreated from multiple layers. By way of example, a “T” shaped flange maybe created from a set of rectangularly shaped layers or components. Withreference to FIG. 5C, a method of forming protrusions on a metal part bysubstantially stacking flange components on a surface of the metal partwill be described in accordance with an embodiment of the presentinvention. A process 541 of forming protrusions on a substrate bysubstantially stacking flange components begins at step 545 in which asubstrate such as a metal part is obtained. Flange components are thenobtained in step 549. Obtaining flange components may include obtainingdifferent pieces or parts used to create a single flange.

In step 553, a first component of each flange that is to form aprotrusion is attached to the substrate. As shown in FIG. 6A, a firstcomponent 612 a of an flange 612 is attached to a substrate 604. Thefirst component of each flange may be attached using any suitablemethod. Once the first component of each flange that is to form aprotrusion is attached to the substrate, a second component of eachflange is stacked and attached in step 557 to the first component, e.g.,using a relatively high bond adhesive. With reference to FIG. 6A, asecond component 612 b may be stacked on and attached to first component612 a.

After the second component of each flange is stacked on and attached tothe first component of each flange, process flow proceeds to step 561 inwhich it is determined if there are additional components to attach.That is, it is determined whether each flange includes at least oneadditional component that has yet to be attached. If it is determinedthat there are no additional components to attach, the indication isthat the protrusions on the substrate are formed, and the process offorming protrusions on a substrate by substantially stacking flangecomponents is completed.

Alternatively, if the determination in step 561 is that there is atleast one additional component to attach, the implication is that eachflange includes at least one additional component. As such, in step 565,the additional component is stacked on and attached appropriately to astack of components that is associated with a flange, e.g., stacked onand attached to the highest component in a stack of components. By wayof example, a third component 612 c may be stacked on and attached tocomponent 612 b of FIG. 6A. Once the additional component is attachedappropriately, process flow returns to step 561 in which it isdetermined if there is an additional component to attach.

In one embodiment, forming binding features that are protrusions mayinclude extruding materials through relatively small openings, as forexample micro perforations, in a substrate. FIG. 5D is a process flowdiagram which illustrates a method of forming protrusions on a substratesuch as a metal part by back filling micro perforations defined withinthe substrate and extruding the material in the micro perforations inaccordance with an embodiment of the present invention. A process 581 offorming protrusions through a back filling and extrusion process beginsat step 583 in which a substrate is obtained. Micro perforations arecreated in the substrate in step 583. A process such as a drillingprocess may be used to create the micro perforations. Alternatively, themicro perforations may be created using a laser or an extrusion process.Typically, the micro perforations may be of a size that essentiallyrenders the micro perforations as substantially invisible. That is, themicro perforations may be small enough not to be readily visible to thehuman eye.

After the micro perforations are created in the substrate, the microperforations are back filled in step 587 with a material that may beextruded. By way of example, the micro perforations may be back filledwith an ultra violet (UV) cured glue. The material may then be extrudedthrough the micro perforations such that protrusions are formed from thematerial in step 589. The shape of the protrusions formed through anextrusion process may vary widely. As shown in FIG. 6B, protrusions 662a-d formed with respect to a substrate 654 may include, but are notlimited to including, a relatively elongated protrusion 662 a, a curledprotrusion 662 b, a short protrusion 662 c, and/or an relativelyelongated protrusion 662 d with a curled end. Bottoms of protrusions662, as shown, generally do not extend past a bottom of substrate 654.Returning to FIG. 5D, the process of forming protrusions using backfilling and extrusion is completed once the material is extruded.

A sputtering process may also be used to form protrusions on asubstrate. FIG. 5E is a process flow diagram which illustrates a methodof forming protrusions on a substrate by sputtering matter onto asurface of the substrate in accordance with an embodiment of the presentinvention. A process 591 of creating protrusions through a sputteringprocess begins at step 593 in which a substrate, as for example a metalpart, is obtained. Matter, e.g., matter used in bone growth sputtering,is sputtered onto a surface of a substrate using a magnetron device instep 589. The sputtering is controlled in step 593 such that chunks ofthe matter may form protrusions of an approximately desired shape andsize. The process of creating protrusions through a sputtering processis then completed.

As previously mentioned, in lieu of creating binding features on thesurface of a substrate which protrude off of the surface, bindingfeatures may be created such that the surface of a substrate issubstantially undercut. In other words, binding features may includeundercuts or voids located substantially below a surface of a substrate.Like the surfaces of protrusions, the surfaces of undercuts or voids ina substrate provide additional surface area to which a moldable materialmay bind, thereby increasing the overall strength of the bond betweenthe moldable material and the substrate.

A variety of different methods may be used to create undercuts on ametal part. FIG. 7A is a process flow diagram which illustrates a methodof forming undercuts on a substrate such as a metal part that includesproviding a pattern on the substrate in accordance with an embodiment ofthe present invention. A process 701 of forming undercuts on a substrateby providing a pattern begins at step 705 in which a substrate, e.g., ametal part, is obtained. Once the substrate is obtained, a desiredpattern is provided in step 709 on the surface of the substrate in whichundercuts are to be created. By way of example, the surface of thesubstrate is masked or screen printed. Masking a pattern allows someportions of the surface of the substrate to remain exposed, while othersare effectively hidden. Screen printing allows a pattern, as for examplea pattern of perforations, to be printed on the surface of the substratesuch that material that is to be removed from the substrate may beidentified.

After the desired pattern is applied to the surface, slightly raisedareas are formed according to the desired pattern in step 713. Theslightly raised areas may be formed by a process such as physical vapordisposition (PVD), for example. In one embodiment, the slightly raisedareas may have an approximate mushroom shape. Once the slightly raisedareas are formed, portions of the pattern that are not in contact withslightly raised areas may be removed in step 717. If the pattern isformed from screen printing, the screen printing may be washed away.When the portions of the pattern are removed, undercuts may remain underthe slightly raised areas, e.g., the tops of the mushroom shaped raisedareas. Upon removing the remaining portions of the pattern, the processof forming undercuts on a substrate by providing a pattern is completed.

Attachment features such as undercuts or voids may also be formed byetching, e.g., chemical and/or mechanical etching. Referring next toFIG. 7B a method of forming undercuts on a substrate that includeschemical etching will be described in accordance with an embodiment ofthe present invention. A process 721 of forming undercuts begins at step725 in which a substrate is obtained. Once the substrate is obtained, adesired pattern may be provided on an appropriate surface of thesubstrate in step 729. In one embodiment, an appropriate surface of thesubstrate may be masked. After the appropriate surface of the substrateis masked or otherwise patterned, chemicals are applied in step 733 tochemically etch the substrate. The application of chemicals may createvoids and/or undercuts.

It should be appreciated that a substrate may include various grains.Specific chemicals may be applied to remove portions of particulargrains, while effectively leaving other grains unaffected. That is,different grains in the substrate may be attacked at different rates.The application of chemicals to chemically etch the substrate mayinclude washing away the chemicals and the removed grains after voidsand/or undercuts are created. The process of forming undercuts iscompleted after chemicals are applied in step 733.

Undercuts or voids may effectively be mechanically etched or cut intothe surface of a substrate. Cutting may be performed using substantiallyany suitable cutting apparatus including, but not limited to including,computer numerical control (CNC) machinery that is configured to cut.FIG. 7C is a process flow diagram which illustrates a method of creatingan undercut in a substrate that includes using a cutting apparatus inaccordance with an embodiment of the present invention. A process 741 ofcreating an undercut begins at step 745 in which a substrate obtained.From step 745, process flow moves to step 749 in which the substrate isplaced or otherwise positioned on a cutting apparatus. Once thesubstrate is placed on the cutting apparatus, the cutting apparatus maybe programmed in step 753 to cut or otherwise form undercuts in desiredlocations. In one embodiment, the cutting apparatus may be programmed tocut “T” shaped voids or undercuts. It should be appreciated thatprogramming a cutting apparatus may include providing the cuttingapparatus with an appropriate cutting bit that may be used to cut voidsor undercuts of a desired size and shape. After the cutting apparatus isprogrammed, the cutting apparatus is used to form undercuts in step 757.The cutting apparatus may mill, scrape, or cut away portions of thesurface of the substrate to form undercuts. The process of creating anundercut is completed upon using the cutting apparatus to formundercuts.

Laser cutting methods may also be used to form undercuts or voids on thesurface of a substrate. FIG. 7D is a process flow diagram whichillustrates a method of creating an undercut that includes using atleast one laser in accordance with an embodiment of the presentinvention. A process 761 of creating an undercut begins at step 765 inwhich a substrate such as a metal part is obtained. Once the substrateis obtained, the substrate is positioned under, or in the path of, atleast one laser in step 769.

In one embodiment, after the substrate is positioned, a lens may bepositioned between the laser and the substrate in order to focus thelaser onto appropriate sections of the substrate in step 773. That is,the lens is configured to focus the laser onto desired areas on asurface of the substrate. Step 773 is optional in that a laser may beused without a lens.

In step 777, the laser is pointed at the substrate such that the surfaceof the substrate may be cut into. By moving the laser and/or thesubstrate, an undercut or void of an appropriate size and shape may becreated. After the surface of the substrate is cut into, the process ofcreating an undercut is completed.

Sections of a substrate may be substantially directly melted away tocreate undercuts or voids. FIG. 7E is a process flow diagram whichillustrates a method of creating an undercut in a substrate thatincludes using at least one hot probe to melt away portions of thesubstrate in accordance with an embodiment of the present invention. Aprocess 781 of creating an undercut begins at step 785 in which asubstrate is obtained. Heated probes are applied to an appropriatesurface of the substrate in step 789 to create chromium diffusion inspots on the surface of the substrate. As will be appreciated by thoseskilled in the art, chromium diffusion may render the surface of thesubstrate capable of being corroded.

After chromium diffusion is created in spots, an acid etch is applied tothe substrate in step 793 to cause the spots to corrode. When the spotscorrode, a three-dimensional profile is effectively created on thesurface of the substrate. Hence, undercuts are created on the surface.Once the spots corrode, the process of creating undercuts is completed.

As mentioned above, a molded metal part that includes a metal member anda moldable member may be created through the use of a molding device.One example of a molding device will be described with reference to FIG.8. FIG. 8 is a cross-sectional side view block diagram representation ofa molding device used to create a molded metal part in accordance withan embodiment of the present invention. A molding device or mold 832includes a mold core 832 a and a mold cavity 832 b. A metal part 804onto which a moldable piece is to be molded is arranged to be held bymold core 832 a. A mold cavity 832 b includes an opening 836 into whicha moldable material, e.g., a molten plastic, may be injected. Opening836 is arranged to be positioned over metal part 804 such that a moldedpiece may be formed over and bound to metal part 804. The shape and sizeof opening 836 may vary widely. In one embodiment, opening 836 is shapedsuch that complex mechanical features may be formed from moldablematerial (not shown) which is cured or hardened within opening 836.

With reference to FIGS. 9A-C, a process of creating a molded metal partusing a molding device such as molding device 832 of FIG. 8 will bedescribed in accordance with an embodiment of the present invention.FIG. 9A is a cross-sectional side view block diagram representation of amolding device used to bind a moldable piece onto a metal part thatincludes undercuts in accordance with an embodiment of the presentinvention. A molding device 932 includes a mold core 932 a and a moldcavity 932 b. Mold cavity 932 b includes an opening 936. A metal part904 that includes undercuts 924 is held by mold core 932 a, while moldcavity 932 b is positioned over metal part 904 such that opening 936 isarranged substantially over undercuts 924.

As shown in FIG. 9B, a material 940 may be injected into opening 936.Injecting material 940 into opening 936 includes causing material 940 toeffectively fill undercuts 924. Material 940 may be a molten plastic ora resin that is arranged to cure or otherwise harden when cooled. Whenmaterial 940 cools, material 940 effectively forms a molded piece thatis bound to metal part 904. Once material 940 cools, an overall moldedmetal part that includes material 940 and metal part 904 is effectivelycreated. Material 940 is bound or otherwise adhered to metal part 904,as shown in FIG. 9C. Material 940 may have a shape that is formed by thecontours of opening 936. Such a shape may include at least onerelatively complex mechanical feature 942.

The shape and size of binding features may vary widely. In addition, thespacing between adjacent binding features may vary. By way of example,the shape and the dimensions associated with undercuts or voids may varydepending upon the requirements of a particle system. In general, thedepth of an undercut or void is less than or approximately equal to thethickness of a substrate or metal part. For a void that is approximatelyequal to the thickness of a substrate, when a moldable material isprovided in the void such that a protrusion is effectively formed on atop surface of the substrate, the moldable material does not protrudepast the bottom surface of the substrate. In other words, moldablematerial substantially only protrudes out of one end of a void. Toefficiently prevent moldable material from protruding past the bottomsurface of a substrate, voids may be shaped such that moldable materialmay be substantially prevented from flowing out of the bottom of thevoid. In one embodiment, a void that may prevent moldable material fromflowing out of the bottom of the void may be substantially tapered,e.g., may have a substantially conical shape.

FIG. 10 is a cross-sectional side view diagrammatic representation of ametal part into which tapered voids have been formed in accordance withan embodiment of the present invention. A metal part 1004 has a heightor a thickness “t” 1044. Typically, a void or undercut may have a heightthat is less than or approximately equal to thickness “t” 1044. In theembodiment as shown, voids 1024 have a height that is approximatelyequal to thickness “t” 1044. Voids 1024 are tapered or substantiallyconical in shape, such that at a top surface 1050, voids 1024 have awidth “w1” 1058, and at a bottom surface 1054, voids 1024 have a width“w2” 1062. Width “w1” 1058 is generally larger than width “w2” 1062.

Although only a few embodiments of the present invention have beendescribed, it should be understood that the present invention may beembodied in many other specific forms without departing from the spiritor the scope of the present invention. By way of example, while thepresent invention has been described in terms of metal parts, thepresent invention is not limited to being used with respect to metalparts. Rather than being formed from metal, a substrate onto whichfeatures are to be adhered may be fabricated from other materialsincluding, but not limited to including, glass or ceramic.

A moldable material from which features are formed may be formed fromsubstantially any suitable plastic or resin. For instance, a moldablematerial may be formed from a plastic such as polycarbonate oracrylonitrile butadiene styrene (ABS). It should be appreciated that amoldable material is not limited to being a plastic or a resin. By wayof example, a moldable material may be an injectable ceramic, or amoldable or injectable metal such as LiquidMetal. Liquid metals, and theuse thereof, are described in U.S. Provisional Application No.60/949,449, filed Jul. 12, 2007, and entitled “INSERT MOLDING LIQUIDMETAL AROUND GLASS,” which is hereby incorporated herein by reference inits entirety.

While the surface of a metal part which is to be bound to a moldablepart has generally been described as including either protrusions orundercuts, the surface of a metal part is not limited to includingeither protrusions or undercuts. For instance, the surface of a metalpart to which a moldable part is to be adhered may include bothprotrusions and undercuts. Further, the sizes and the shapes ofprotrusions and undercuts associated with the surface of a metal partmay vary. In one embodiment, protrusions of different shapes and/orundercuts of different shapes may be associated with a single metalpart.

The steps associated with the methods of the present invention may varywidely. Steps may be added, removed, altered, combined, and reorderedwithout departing from the spirit of the scope of the present invention.By way of example, chemically etching undercuts and/or voids in asubstrate may include applying a first set of chemicals to etch peaksand valleys on the surface of a substrate, providing a liquid in thevalleys, polishing the surface, and then applying a second set ofchemicals that “eats” the liquid in the valleys at different rates thanthe surface to create undercuts. Therefore, the present examples are tobe considered as illustrative and not restrictive, and the invention isnot to be limited to the details given herein, but may be modifiedwithin the scope of the appended claims.

What is claimed is:
 1. A housing for a mobile phone, comprising: a metalpart defining: a cosmetic exterior surface of the housing; a bondingregion internal to the housing; and a plurality of recesses formed intothe metal part along the bonding region, a recess of the plurality ofrecesses defined by: an opening in the bonding region of the metal part;and a chamber in communication with the opening, the opening beingnarrower than the chamber to define an undercut; and a molded plasticpiece contacting the metal part and having portions extending into eachrecess of the plurality of undercut recesses to affix the molded plasticpiece to the metal part; wherein a thickness of a first portion of themetal part defined between a surface of the chamber and the cosmeticexterior surface of the housing is less than a thickness of a secondportion of the metal part adjacent the recess.
 2. The housing of claim1, wherein the metal part and the molded plastic piece cooperate todefine a smooth surface.
 3. The housing of claim 1, wherein; the metalpart is a first metal part; and the molded plastic piece is furtheraffixed to a second metal part.
 4. The housing of claim 1, wherein therecess of the plurality of recesses is defined in cross-section by atleast one curved surface.
 5. The housing of claim 1, wherein theplurality of recesses are formed by chemical etching.
 6. The housing ofclaim 1, wherein the recess of the plurality of recesses is defined by amachined recess surface.
 7. The housing of claim 1, wherein the moldedplastic piece fills the chamber and the opening.
 8. A mobile phone,comprising: a housing comprising: a metal part defining: an exteriorsurface of the housing; and a void machined into the metal part anddefining: an opening; and a chamber in communication with the opening,the opening being narrower than the chamber to define an undercut; and aunitary molded plastic piece filling the void and engaging the undercutto retain the unitary molded plastic piece to the metal part; and aplurality of electronic components contained within the housing; whereina first portion of the metal part that defines the void is thinner thana second portion of the metal part adjacent the void.
 9. The mobilephone of claim 8, wherein the metal part and the unitary molded plasticpiece cooperate to define a smooth surface.
 10. The mobile phone ofclaim 8, wherein: the void defines: a first void region; and a secondvoid region contiguous with the first void region; the second voidregion is undercut with respect to the first void region; and theunitary molded plastic piece occupies the first void region and thesecond void region.
 11. The mobile phone of claim 8, wherein the metalpart is formed of stainless steel or aluminum.
 12. The mobile phone ofclaim 8, wherein the unitary molded plastic piece is formed from anonconductive plastic.
 13. The mobile phone of claim 8, wherein: thevoid is a first void; the metal part further defines a second void; andthe unitary molded plastic piece further fills the second void.
 14. Ahandheld electronic device, comprising: a housing structure, comprising:a metal part defining: at least a portion of an internal volume of thehandheld electronic device; an exterior surface of the handheldelectronic device; and a recess defined by: an opening in the metalpart; and a chamber in communication with the opening, the opening beingnarrower than the chamber to define and undercut; and a unitary plasticpiece having a portion formed within the recess and retained to themetal part via the undercut, the unitary plastic piece defining aportion of an internal surface of the housing structure; and a pluralityof electronic components within the internal volume; wherein a firstportion of the metal part that defines the recess is thinner than asecond portion of the metal part adjacent the recess.
 15. The handheldelectronic device of claim 14, wherein the unitary plastic piece definesa screw boss having an opening configured to receive a screw.
 16. Thehandheld electronic device of claim 14, wherein the recess is formed bychemical etching.
 17. The handheld electronic device of claim 14,wherein the recess is formed by machining.
 18. The handheld electronicdevice of claim 17, wherein: the metal part defines a plurality ofadditional recesses; and the unitary plastic piece extends into theplurality of additional recesses.